Fresh blood always seems to creep into the NFL playoffs. In the AFC, two first-year coaches shocked everyone, and it's guaranteed that one first-year coach will be in the conference's final four.

Tony Sparano turned a 1-15 Dolphins team into an 11-5 winner of the AFC East, sealing his incredible story with a 24-17 victory over the Jets on Sunday in the Meadowlands. The Ravens' John Harbaugh, a special-teams coach two years ago and a linebackers coach for the Eagles last season, rode a great defense and rookie quarterback Joe Flacco to an 11-5 season. Fittingly, the Ravens travel to Miami on Sunday in the first round of the playoffs. An added twist is the return of Cam Cameron, who flopped as Miami's head coach last season but has helped groom Flacco as Baltimore's offensive coordinator.

The Dolphins and Ravens are the only two teams that weren't in the AFC playoffs last season. The rest of the teams are making repeat appearances, though there have been significant role changes. The Titans are the top seed, while the Colts, who owned the AFC South the previous five years, are the top wild-card team. The Chargers and Steelers have been playoff staples, although San Diego barely made it after rebounding from a 4-8 start.

1. What are the most anticipated games?

Without question, if the Steelers meet the Titans in an AFC Championship Game, it could be a classic. Steelers players and fans were furious when they saw Titans linebacker Keith Bulluck and others stomping on a Terrible Towel following Tennessee's 31-14 victory over the Steelers in Week 16.

Although a third meeting between the Colts and Titans could be interesting, the better game might be Colts-Steelers in the second round. The Colts beat the Steelers 24-20 in Pittsburgh in Week 10. The game was a classic. The Steelers jumped out to a 17-7 lead, but Peyton Manning engineered a 70-yard touchdown drive before halftime and put together two more touchdown drives in the second half to clinch the victory.

2. What are the key rematches in the wild-card round?

The Colts went to San Diego in Week 12 and beat the Chargers 23-20, thanks to a 51-yard field goal by Adam Vinatieri at the end of regulation. In Week 7, the Ravens beat the Dolphins 27-13 at Dolphin Stadium. The most interesting aspect of that game was how the Ravens' defense stopped the Dolphins' Wildcat running formation. Ronnie Brown was held to 27 yards on 13 carries, while Ricky Williams had 16 yards on four carries. The Ravens jumped to a 17-6 lead in the second quarter and weren't challenged much after that.

3. Where will injuries be a concern?

Steelers quarterback Ben Roethlisberger was carted off Heinz Field on Sunday and taken by ambulance to a nearby hospital. The team says he suffered a concussion in Pittsburgh's 31-0 victory over the Browns, but tests for additional injuries were negative, according to a source. Big Ben's status will be closely monitored over the next two weeks, but you figure he'll be able to play. Other than Roethlisberger, the Steelers should be in good shape because they were able to rest safety Ryan Clark (shoulder) and linebacker James Harrison (hip) against the Browns.

Titans coach Jeff Fisher is optimistic defensive tackle Albert Haynesworth (knee), defensive end Kyle Vanden Bosch (groin) and center Kevin Mawae (elbow) should be back for the divisional playoffs. The Colts expect linebacker Freddy Keiaho (hamstring) to be back for the wild-card round, but middle linebacker Gary Brackett (fibula) may not be back until the second round or maybe the championship game. Safety Bob Sanders sat out Sunday's 23-0 win over the Titans. Unless there is swelling in his knee this week, he should be ready for the wild-card game. The one concern for the Chargers is the abdominal strain sustained by LaDainian Tomlinson against the Broncos on Sunday night. His status for next Saturday's wild-card game against the Colts is in question.

4. Which teams boast the best running games?

The Titans average 137.4 rushing yards and 31.75 carries a game, while the Ravens average 148.5 rushing yards and 37 attempts. The Dolphins use the gimmicky Wildcat to catch teams off guard. Their numbers are modest -- 118.6 rushing yards and 28 carries a game -- but they get the most out of those confusing formations.

For various reasons, the Chargers, Colts and Steelers have been unsuccessful running the ball this season Injuries limited the Colts' Joseph Addai to 540 yards after a Pro Bowl season in 2007. Willie Parker's knee problems made the Steelers rely on the pass instead of their traditional power running game. Chargers running back LaDainian Tomlinson has had one of the worst seasons of his career. Shaky run-blocking by the Chargers' offensive line hasn't helped, but he's probably lost half a step.

5. What types of games will the defenses dictate?

Expect a lot of wild blitzing and possibly a lot of big plays if linebackers or defensive backs don't get to the quarterback. Four of the six AFC teams use 3-4 defenses (only the Colts and Titans use the 4-3). Over the years, Manning has gotten better against 3-4 defenses because of his preparation and the way he times his pass routes with his wide receivers and tight end Dallas Clark. Ravens defensive coordinator Rex Ryan came into Lucas Oil Stadium with an aggressive game plan in Week 6, but Manning whipped the Ravens 31-3. The Dolphins blitz out of their 3-4 with Joey Porter, who had 17½ sacks. The Steelers have James Harrison and LaMarr Woodley, who combined for 27½ sacks.

The 3-4 teams could cause problems for Roethlisberger, Flacco, Philip Rivers of the Chargers and Kerry Collins of the Titans because they aren't very mobile. Manning and Chad Pennington of the Dolphins can neutralize a pass rush with quick passes.

6. Which quarterbacks hold the edge?

Manning, Roethlisberger and -- believe it or not -- Collins have the edge. Manning is the most experienced playoff quarterback. He's been in 14 playoff games, winning seven and losing seven. He has 21 touchdown passes and 17 interceptions in those 14 games, and he's completed 61 percent of his passes. He's won three of his past four playoff games, and he has a Super Bowl ring.

Roethlisberger is next. In the postseason, he's 5-2 with 12 touchdown passes and 11 interceptions, and he has the league's highest completion percentage (62.4). Collins is the sleeper. He's been to two conference championship games and a Super Bowl. Pennington is a solid playoff quarterback. He took three Jets teams to the playoffs and is 2-3 in the postseason with seven touchdown passes and a 60.4 completion percentage. Rivers is just starting to learn how to be a successful playoff quarterback. He is 2-2 in the postseason, thanks to last season's run to the AFC title game.

7. Is there an edge in coaching?

Clearly, Fisher and the Colts' Tony Dungy are seasoned playoff veterans. Veteran playoff coaches don't let their players get too high for playoff games. Dungy learned about playoff coaching from his mentor, Chuck Noll, who won four Super Bowls with the Steelers. Dungy's calm presence has been a fixture on the sidelines for 18 playoff games, tops among this year's AFC playoff coaches. He's 9-9 in those games.

Fisher is 5-5 and has been to the Super Bowl. Thanks to his two playoff wins in 2007, the Chargers' Norv Turner is 3-2. The Steelers' Mike Tomlin made the playoffs last season but lost to the Jaguars at home. Harbaugh and Sparano are making their first playoff appearances.

8. If it comes down to a field goal, who has the edge?

This may be hard to believe, but there isn't a bad kicker in the group. In fact, the Colts' Adam Vinatieri -- the best clutch kicker in this era -- might have had the shakiest season, going 20-of-25 on field goals. The Ravens' Matt Stover was 27-of-33. The Titans' Rob Bironas had the best season, going 29-of-33. The Steelers' Jeff Reed was 27-of-31 and the Chargers' Nate Kaeding was 27-of-32. Miami's Dan Carpenter is the rookie of the group, but he had a great season, going 21-of-25. This was the greatest year for kickers, as far as accuracy and distance are concerned, in the history of the league.

9. Which defense will have the biggest chip on its shoulder?

The Steelers. They had one of the greatest statistical seasons in league history. They allowed only 3.9 yards a play, 237.2 yards a game and 3.3 rushing yards a carry. They had 51 sacks, and opposing quarterbacks posted a 63.4 rating against them. The Ravens are next. Their secondary allowed only 5.9 yards per pass attempt while opposing quarterbacks had a 60.6 rating against them. The Titans have one of the hardest-hitting defenses in the league and will be welcoming the return of Haynesworth, perhaps the most dominating defender in the AFC.

The Colts and Chargers have the biggest worries. Small against the run and vulnerable against the pass, the Colts' defense relies on Manning to put together long drives that will keep opposing offenses off the field. If Manning can get a lead, though, the Colts have enough pass-rushers to seal a victory.

10. Is there anything we've learned from these six teams?

Just as we saw with the Giants last year, the hot teams have the edge come playoff time. It's not how you start, it's how you finish. The Dolphins rebounded from a 2-4 start to win nine of their final 10, including their last five. The Colts won nine in a row after a 3-4 start. The Ravens rebounded from a 2-3 start with nine wins in their last 11 games. The Chargers won their final four games to become the first team in NFL history to make the playoffs after starting 4-8. The Steelers won six of their final seven, while the Titans had the AFC's best record at 13-3.

John Clayton, a recipient of the Pro Football Hall of Fame's McCann Award for distinguished reporting, is a senior writer for ESPN.com.